Dendritic Cells in the Breaking of Peripheral Tolerance in Type 1 Diabetes

树突状细胞破坏 1 型糖尿病的外周耐受性

• 批准号: 8327883
• 负责人: Edith M Janssen
• 金额: $ 28.02万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-20 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8327883
• 关键词: Animals; Antigen-Presenting Cells; Antigens; Apoptotic; Autoantigens; Autoimmune Diabetes; Autoimmune Diseases; Beta Cell; CD4 Positive T Lymphocytes; CD81 gene; CD8B1 gene; Cells; Childhood; Clonal Expansion; Cross-Priming; Cytoplasm; Data; Dendritic Cells; Development; Diabetes Mellitus; Disease; Exhibits; Goals; Greek; Health; Human; ITGAX gene; Immune Tolerance; Immunity; Immunization; In Vitro; Inbred NOD Mice; Individual; Inflammation; Inflammatory; Insulin; Insulin-Dependent Diabetes Mellitus; Interferon Receptor; Interferons; Lead; Mediating; Memory; Modeling; Molecular; Mus; Non obese; Pancreas; Participant; Patients; Peripheral; Phagocytosis; Population; Process; Production; Regulatory T-Lymphocyte; Role; Structure of beta Cell of islet; T cell response; T-Lymphocyte; T-Lymphocyte Subsets; Testing; Time; Tissues; Vesicle; anergy; cytokine; diabetic; feeding; in vivo; islet; lymph nodes; novel; particle; peripheral tolerance

DESCRIPTION (provided by applicant): Type 1 diabetes (T1D), the most common childhood autoimmune disease, is caused by the T lymphocyte-mediated destruction of insulin-producing pancreatic beta cells. The salient immunological features of T1D are well-modeled in the non-obese diabetic (NOD) mouse, which like human T1D patients exhibit spontaneous autoimmune diabetes mediated by both CD4+ and CD8+ T cells. While these diabetogenic, or disease-causing, T cells are indispensable cellular participants, their activation and functional maturation are controlled by the innate antigen presenting cells (APC) which acquire, process and present pancreatic beta cell antigen in a manner that breaks normal peripheral T cell tolerance. The APC responsible for breaking T cell tolerance and the molecular mechanism involved is not well understood. It is well appreciated that dendritic cells (DC) are crucial for presenting foreign antigen to T cells during times of inflammation. Yet, the clearance of apoptotic self cells by DC is generally considered to be non-inflammatory, even tolerogenic; in fact, numerous studies have shown that DC that capture antigen from apoptotic cells migrate to local lymph nodes, where they induce T cell tolerance, anergy or deletion. Yet, under certain situations phagocytosis of apoptotic cells by DC can be pro-inflammatory and lead to the priming of self-reactive T cells; this is thought to be the case for the presentation of apoptotic pancreatic beta cells in T1D-prone individuals or animals. Recently, we found that a subset of conventional DC (cDC) are necessary for priming diabetogenic CD4+ T cells in vivo. Interestingly, within this cDC population, our colleague and dual-PI applicant, Dr. Edith Janssen, described a novel DC subset (CD11c+CD11blo/-CD4-CD81-PDCA-1-) that in contrast to other cDC subsets potently (cross-)primes both CD4+ and CD8+ T cells to self-antigen from apoptotic cells. These cells are termed merocytic DC (mcDC) since they stored particles of apoptotic cells in discrete, punctate vesicles in their cytoplasm, meros (<5A?C, particle, in Greek). For example, CD8+ T cells that encounter mcDC exposed to apoptotic antigen are not rendered tolerant, but rather display enhanced primary clonal expansion, cytokine production and effector function. Moreover, mcDC enhance inflammatory immunity to apoptotic self in part by producing copious levels of type 1 interferons. Rationale: Our recent studies have found that mcDC are not only more numerous but also more biologically active in NOD mice compared to other strains. Islet antigen-loaded mcDC (i) rescue CD8+ T cells from peripheral anergy and deletion, (ii) stimulate islet-reactive CD4+ T cells, and (iii) transfer diabetes to young NOD recipients. Moreover, when purified from the pancreatic lymph nodes of overtly diabetic NOD mice, mcDC can break peripheral T cell tolerance to beta cell antigens in vivo and induce rapid onset T cell-mediated T1D in young NOD mouse. Thus, the mcDC subset appears to represent the long-sought critical antigen presenting cell responsible for breaking peripheral tolerance to beta cell antigen in vivo. Hypothesis: Together, these results lead us to hypothesize that mcDC are (i) the critical CD11c+ DC subset responsible for the priming of diabetogenic T cells and cause the functional break in immune tolerance to islet antigen, and (ii) a major reservoir of type 1 interferon needed to drive T1D in NOD mice. To provide a direct test of these hypotheses, we propose the following specific aims: Aim 1: To identify the means by which islet-antigen-fed mcDC break CD4+ and CD8+ T cell tolerance in the NOD mouse. Preliminary data shows that the acquisition and presentation of self-antigen from apoptotic beta cells breaks peripheral CD4+ and CD8+ T cell tolerance in vivo. Aim 2: To define the molecular role of type 1 interferon production by mcDC in the development of T1D in the NOD mouse. PUBLIC HEALTH RELEVANCE: This application focuses on Type 1 diabetes (T1D), the most common childhood autoimmune disease, is caused by the T lymphocyte-mediated destruction of insulin-producing pancreatic beta cells. The salient immunological features of T1D are well-modeled in the non-obese diabetic (NOD) mouse, which like human T1D patients exhibit spontaneous autoimmune diabetes mediated by both CD4+ and CD8+ T cells. While these diabetogenic, or disease-causing, T cells are indispensable cellular participants, their activation and functional maturation are controlled by the innate antigen presenting cells (APC) which acquire, process and present pancreatic beta cell antigen in a manner that breaks normal peripheral T cell tolerance. The APC responsible for breaking T cell tolerance and the molecular mechanism involved is not well understood. Recently, we found that a subset of conventional DC (cDC) are necessary for priming diabetogenic CD4+ T cells in vivo. Interestingly, within this cDC population, our colleague and dual-PI applicant, Dr. Edith Janssen, described a novel DC subset termed merocytic DC (mcDC) which store particles of apoptotic cells in discrete, punctate vesicles in their cytoplasm. Additionally, mcDC enhance inflammatory immunity to self tissue in part by producing copious levels of type 1 interferons. Our recent studies have found that mcDC are not only more numerous but also more biologically active in NOD mice compared to other strains. We hypothesize that mcDC are (i) the critical CD11c+ DC subset responsible for the priming of diabetogenic T cells and cause the functional break in immune tolerance to islet antigen, and (ii) a major reservoir of type 1 interferon needed to drive T1D in NOD mice.

描述（由申请人提供）：1 型糖尿病 (T1D) 是最常见的儿童自身免疫性疾病，是由 T 淋巴细胞介导的产生胰岛素的胰腺 β 细胞的破坏引起的。 T1D 的显着免疫学特征在非肥胖糖尿病 (NOD) 小鼠中得到了很好的模拟，与人类 T1D 患者一样，NOD 小鼠也表现出由 CD4+ 和 CD8+ T 细胞介导的自发性自身免疫糖尿病。虽然这些导致糖尿病或致病的 T 细胞是不可或缺的细胞参与者，但它们的激活和功能成熟是由先天抗原呈递细胞 (APC) 控制的，该细胞以破坏正常外周 T 细胞耐受性的方式获取、处理和呈递胰腺 β 细胞抗原。负责破坏 T 细胞耐受性的 APC 及其分子机制尚不清楚。众所周知，树突状细胞 (DC) 对于在炎症期间向 T 细胞呈递外来抗原至关重要。然而，DC对凋亡自身细胞的清除通常被认为是非炎症性的，甚至是耐受性的；事实上，大量研究表明，从凋亡细胞捕获抗原的 DC 会迁移到局部淋巴结，在那里诱导 T 细胞耐受、无反应或缺失。然而，在某些情况下，DC 对凋亡细胞的吞噬可能具有促炎性，并导致自身反应性 T 细胞的启动；这被认为是 T1D 易感个体或动物中出现凋亡的胰腺 β 细胞的情况。最近，我们发现传统 DC (cDC) 的一个子集对于体内启动致糖尿病 CD4+ T 细胞是必需的。有趣的是，在这个 cDC 群体中，我们的同事兼双 PI 申请人 Edith Janssen 博士描述了一种新型 DC 子集 (CD11c+CD11blo/-CD4-CD81-PDCA-1-)，与其他 cDC 子集相比，它能有效（交叉）引发 CD4+ 和 CD8+ T 细胞与来自凋亡细胞的自身抗原。这些细胞被称为粒细胞 DC (mcDC)，因为它们将凋亡细胞颗粒储存在细胞质中离散的点状囊泡中，即 meros（<5A?C，希腊语中的颗粒）。例如，遇到暴露于凋亡抗原的 mcDC 的 CD8+ T 细胞不会产生耐受性，而是表现出增强的初级克隆扩增、细胞因子产生和效应子功能。此外，mcDC 部分通过产生大量 1 型干扰素来增强对凋亡自身的炎症免疫。理由：我们最近的研究发现，与其他品系相比，NOD 小鼠中的 mcDC 不仅数量更多，而且生物活性更高。负载胰岛抗原的 mcDC (i) 将 CD8+ T 细胞从外周无能和缺失中拯救出来，(ii) 刺激胰岛反应性 CD4+ T 细胞，以及 (iii) 将糖尿病转移给年轻的 NOD 受体。此外，当从患有明显糖尿病的 NOD 小鼠的胰腺淋巴结中纯化时，mcDC 可以破坏体内外周 T 细胞对 β 细胞抗原的耐受性，并在年轻的 NOD 小鼠中诱导快速发作的 T 细胞介导的 T1D。因此，mcDC亚群似乎代表了长期寻找的关键抗原呈递细胞，其负责打破体内对β细胞抗原的外周耐受。假设：综合起来，这些结果使我们假设 mcDC 是 (i) 关键的 CD11c+ DC 子集，负责启动致糖尿病 T 细胞并导致对胰岛抗原的免疫耐受功能性破坏，以及 (ii) 在 NOD 小鼠中驱动 T1D 所需的 1 型干扰素的主要储存库。为了对这些假设进行直接检验，我们提出以下具体目标： 目标 1：确定胰岛抗原喂养的 mcDC 破坏 NOD 小鼠 CD4+ 和 CD8+ T 细胞耐受性的方法。初步数据表明，从凋亡的β细胞获取和呈递自身抗原破坏了体内外周CD4+和CD8+T细胞的耐受性。目标 2：确定 mcDC 产生的 1 型干扰素在 NOD 小鼠 T1D 发展中的分子作用。 公共健康相关性：本申请重点关注 1 型糖尿病 (T1D)，这是最常见的儿童自身免疫性疾病，是由 T 淋巴细胞介导的产生胰岛素的胰腺 β 细胞破坏引起的。 T1D 的显着免疫学特征在非肥胖糖尿病 (NOD) 小鼠中得到了很好的模拟，与人类 T1D 患者一样，NOD 小鼠也表现出由 CD4+ 和 CD8+ T 细胞介导的自发性自身免疫糖尿病。虽然这些导致糖尿病或致病的 T 细胞是不可或缺的细胞参与者，但它们的激活和功能成熟是由先天抗原呈递细胞 (APC) 控制的，该细胞以破坏正常外周 T 细胞耐受性的方式获取、处理和呈递胰腺 β 细胞抗原。负责破坏 T 细胞耐受性的 APC 及其分子机制尚不清楚。最近，我们发现传统 DC (cDC) 的一个子集对于体内启动致糖尿病 CD4+ T 细胞是必需的。有趣的是，在这个 cDC 群体中，我们的同事兼双 PI 申请人 Edith Janssen 博士描述了一种称为粒细胞 DC (mcDC) 的新型 DC 子集，它将凋亡细胞颗粒储存在细胞质中离散的点状囊泡中。此外，mcDC 部分通过产生大量 1 型干扰素来增强自身组织的炎症免疫。我们最近的研究发现，与其他品系相比，NOD 小鼠中的 mcDC 不仅数量更多，而且生物活性更高。我们假设 mcDC 是 (i) 关键的 CD11c+ DC 子集，负责启动致糖尿病 T 细胞并导致对胰岛抗原的免疫耐受功能破坏，以及 (ii) 在 NOD 小鼠中驱动 T1D 所需的 1 型干扰素的主要储存库。